PURPOSE: To attain the parameter-dependent control of a reaction force at an operating element by controlling an electric motor depending on parameters for the analog quantities changed against the operating force to be applied to the operating element.

CONSTITUTION: The output side of an electric or electronic control device 14 is connected to an electric motor 13, and the input side is connected to a torque sensor 15. Another input side 16 is connected to a prescribed parameter, e.g. a travel speed signal generator of a vehicle. The electric motor 13, which generates an additional steering auxiliary force to decrease the manual force to be applied to a steering wheel 1 by a driver, is controlled differently according to the travel speed. The analog auxiliary force changed against the force applied to a steering link mechanism 3 on the travel speed is generated. The operation of the electric motor 13 is stopped at a high travel speed to decrease the force applied to the steering wheel 1.